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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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b92ad209c2
This patch is originally based on commit b3377d1865 ("ARM: 7064/1:
vexpress: Use wfi macro in platform_do_lowpower.")
Current Exynos CPU hotplug code includes a hardcoded WFI instruction,
in ARM encoding. When the kernel is compiled in Thumb-2 mode, this
is invalid and causes the machine to hang hard when a CPU is offlined.
Use wfi macro instead of the hardcoded WFI instruction.
Signed-off-by: Leela Krishna Amudala <leela.krishna@linaro.org>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
91 lines
1.8 KiB
C
91 lines
1.8 KiB
C
/* linux arch/arm/mach-exynos4/hotplug.c
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*
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* Cloned from linux/arch/arm/mach-realview/hotplug.c
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*
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* Copyright (C) 2002 ARM Ltd.
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* All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/smp.h>
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#include <linux/io.h>
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#include <asm/cacheflush.h>
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#include <asm/cp15.h>
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#include <asm/smp_plat.h>
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#include "common.h"
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#include "regs-pmu.h"
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static inline void cpu_leave_lowpower(void)
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{
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unsigned int v;
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asm volatile(
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"mrc p15, 0, %0, c1, c0, 0\n"
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" orr %0, %0, %1\n"
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" mcr p15, 0, %0, c1, c0, 0\n"
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" mrc p15, 0, %0, c1, c0, 1\n"
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" orr %0, %0, %2\n"
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" mcr p15, 0, %0, c1, c0, 1\n"
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: "=&r" (v)
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: "Ir" (CR_C), "Ir" (0x40)
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: "cc");
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}
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static inline void platform_do_lowpower(unsigned int cpu, int *spurious)
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{
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for (;;) {
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/* make cpu1 to be turned off at next WFI command */
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if (cpu == 1)
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exynos_cpu_power_down(cpu);
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wfi();
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if (pen_release == cpu_logical_map(cpu)) {
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/*
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* OK, proper wakeup, we're done
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*/
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break;
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}
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/*
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* Getting here, means that we have come out of WFI without
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* having been woken up - this shouldn't happen
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*
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* Just note it happening - when we're woken, we can report
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* its occurrence.
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*/
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(*spurious)++;
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}
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}
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/*
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* platform-specific code to shutdown a CPU
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*
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* Called with IRQs disabled
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*/
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void __ref exynos_cpu_die(unsigned int cpu)
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{
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int spurious = 0;
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v7_exit_coherency_flush(louis);
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platform_do_lowpower(cpu, &spurious);
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/*
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* bring this CPU back into the world of cache
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* coherency, and then restore interrupts
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*/
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cpu_leave_lowpower();
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if (spurious)
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pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious);
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}
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